What is Concurrent Training?

What is Concurrent Training?

Concurrent training is a program design that combines resistance training and endurance work in the same training block. Rather than dedicating separate blocks to 'get strong' then 'get fit,' concurrent training runs both qualities side by side — for example, three lifting sessions and two runs in the same week. It's the default setup for most general-population lifters, team-sport athletes, and anyone training for a hybrid goal, like a powerlifter who also runs or a runner who also lifts, and it's the subject of decades of research into whether combining the two blunts either one.

How it works

Concurrent training works — and sometimes underperforms single-mode training — because of what's called the interference effect. Resistance training signals a cellular pathway (mTOR) that drives muscle protein synthesis and growth, while endurance training activates a different pathway (AMPK) that drives mitochondrial growth and fat oxidation; at a high enough dose, AMPK activation can blunt the mTOR signal, theoretically capping strength and size gains. In practice, most current research finds this interference is small and manageable at realistic training volumes — it becomes a real problem mainly when endurance volume is very high, such as marathon training, or when both modalities are trained hard with too little recovery between them.

How to apply it

• Separate sessions by time: Where possible, put strength and endurance work in different sessions (e.g. lift in the morning, run in the evening) rather than back to back, to reduce acute interference.
• Order matters within a session: If you must combine both in one session, most research favors doing strength work first when strength is the priority, since fatigue from cardio blunts a subsequent lifting session more than the reverse.
• Manage total volume: Interference grows with endurance volume — 2-3 moderate cardio sessions a week is well tolerated by most lifters; 5-6 hard endurance sessions is where meaningful interference tends to show up.
• Prioritize one quality per phase: During a strength-focused block, keep cardio to a maintenance dose (short, easy sessions); during an endurance-focused block, do the same with lifting.

Worked example

Here's a sample weekly split for a lifter adding running without derailing strength gains.

Hard running days are paired with easier lifting days (and vice versa) so peak fatigue from one doesn't stack directly on the other.

Concurrent training vs. single-mode training

For most lifters who aren't competing at an elite level, the interference cost of 2-3 cardio sessions a week is small enough that concurrent training is the practical default.

By goal

• General lifters: 2-3 moderate cardio sessions a week alongside a normal lifting program carries minimal interference risk.
• Hybrid/CrossFit-style athletes: Separate hard cardio and hard lifting by at least 6-8 hours, and avoid hard-stacking both on the same day back to back if possible.
• Competitive powerlifters/marathoners near a meet or race: Temporarily minimize the secondary modality — the interference cost of high-volume concurrent training matters more the closer you are to peaking.

Common misconceptions

• "Any cardio will kill your gains." Research shows the interference effect is real but modest at typical training volumes — 2-4 moderate cardio sessions a week alongside a structured lifting program produces little to no measurable strength or size penalty.
• "Concurrent training is only a problem for bodybuilders." The interference effect is best documented in studies measuring strength and hypertrophy, but it can run both ways — high lifting volume can also blunt endurance adaptations in athletes prioritizing running or cycling performance.
• "You must always lift before you run (or vice versa) in the same session." Sequencing matters most when both are trained hard in the same session; if you prioritize strength, lift first while fresh, but on easier days the order matters far less.

Related terms

Concurrent Training FAQ

Does cardio really interfere with muscle and strength gains?

Research shows a real but generally small 'interference effect' at typical training volumes — 2-4 moderate cardio sessions a week alongside a structured lifting program cost little to no measurable strength or size, though very high endurance volume can blunt gains more.

Should I run before or after lifting?

If building strength or muscle is your priority, lift first while fresh; if endurance performance is the priority, do the harder cardio session first. Separating them by several hours reduces the trade-off either way.

How much cardio can I do without losing muscle?

Most lifters tolerate 2-4 moderate-intensity cardio sessions (20-40 minutes) per week with minimal impact on strength or hypertrophy, provided total recovery and protein intake stay adequate.

What is the interference effect in concurrent training?

It's the phenomenon where combining endurance and resistance training can blunt the muscle-building (mTOR) signal via a competing endurance-adaptation pathway (AMPK), theoretically capping strength and size gains compared to lifting alone.

Can you get strong and build endurance at the same time?

Yes — most recreational and even many competitive athletes build both simultaneously; the interference effect mainly becomes limiting at very high combined volumes or when both are trained hard with too little recovery.

References

1. Optimizing concurrent training programs: a review on factors that enhance muscle strength PMC11688070
2. The Role of Intra-Session Exercise Sequence in the Interference Effect: A Systematic Review with Meta-Analysis PMC5752732
3. Concurrent Training and the Interference Effect: Will Cardio Kill Your Gains? Barbell Medicine
4. Research Spotlight: The interference effect is getting less scary by the day Stronger by Science